Means for the electrolytic manufacture of sodium.



P. L. HULIN. MEANS FOR THE ELECTROLYTIC MANUFACTURE or SODIUM.

APPLICATION FILED 0OT.27, 1908. 4 9'?9,497 Patented De0.27, 1910.

3 SHEETS-SHEET 1.

WITNESSES. INVEA/TUR g v my; Lia/v 1101.)

P. L. HULIN.

MEANS FOR. THE ELECTROLYTIC MANUFACTURE OF SODIUM.

APPLIOATION FILED OCT. 27, 1908.

Patented De0.27, 1910.

3 BHBBTB-BHEET 2.

WIT/M55555.

ATTORNEYS P. L. HULIN.

MEANS FOR THE ELEOTROLYTIG MANUFACTURE or SODIUM.

APPLICATION FILED 0GT.27, 1908.

Patented Dec. 27, 1910.

3 SHEETS-SHEET 3L PAUL LEO/V HUL/N WITNESSES. %%W

ATTORNEYS PAUL LEON HULiN, or GRENOBLE, FRANCE, AssieNon ro 'sooin'rn DELECTRO-GHIMIE, or PARIS, FRANCE, AND PAUL LEON HULIN, or GRENOBLE, FRANCE.

MEANS FORTHE ELECTROLYTIC MANUFACTURE OF SODIUM.

Specification of Letters Patent. Patented Dec. 2?, i910.

Application and October 27,4908. Serial No. 459,728.

to. the manufacture of sodium by the elec trolysis of fused caustic soda.

When fused caustic soda is treated by the electric current the oxygen passes to the anspecialized conditions and with the aid of appropriate apparatus. The principal difficulty would appear to be attributable to the intimate association of the freshly producedv sodium and hydrogen. The formation of this gas at the cathode causes an ebullition which, owing to the lightness of the metal disperses the latter into the electrolyte and subdivides it into minute particles which, having no common ascensional tendency, are incapable of collecting in a chamber assigned for the purpose. Under these conditions the sodium undergoes veryrapid oxi-' dation both in the bath, throughout which it is so finely dispersed as to practically constitute an emulsion, and also at the surface where it is in'a very finely divided state. Hence it is only possible to collect a very small proportion of the actual yield. The

practical solution of the problem was furnished in the first instance by Castner who invented a special apparatus. By rigorously limiting the ten'iperature of the bath and by the use of a special diaphragm of metallic gauze adapted toconfine the disengaged hydrogen and sodium to a narrow chamber,

for its obj ect' The apparatus, together with its adjuncts,

. which constitutes the subject of the present invention is represented in the accompanying drawings wherein Figure 1 is a horizontal section on line -33 of Fig. 2. Fig. 2 is a vertical section on line 11 of Fig. 1. Fig. 3 is a plan View" of the apparatus, the separator being removed, while Fig. 4 isa vertical section on-l-ine 2-2 of Fig. 3, showing a modifica-.

tion of the separator. Fig. 5 is a horizontal section showin the heating device. Figs. 6-

and 7 are detai ed views of various adjuncts of the apparatus. .Fig. 8 is a plan view and Fig. 9 avertical section of a modification of the apparatus provided with flat 'elec'- trodes.

.The apparatus comprises a vat A of castiron or steel'of any appropriate cross section, but preferably cylindrical or rectangular with rounded angles. A cylinder B of iron or laminated or forged steel is supported in the vat by means of arms C, C of the same material, which also serve to conduct the current (of-positive polarity) to the said cylinder. This'cylinder B constitutes the anode of the apparatus. In the center of the vat is suspended a range of rods or strips of copper which constitutes the cathode, a predetermined annular space separating the electrodes The cathode is thus formed of a circular group of vertical rods t, t, t'of copper mounted upon a crown D of the same metal around its periphery (Figs. 1-2, 3, 4 and 6). A central support (Z with downwardly extending arms suspends this crown at the proper level and supplies to it the current of negative polarity. This support cl is fixed at its upper end to a suitable support through the medium of a nut or the like, permitting the dismounting of the cathode which should ordinarily remaln fixed in position. A .circular ring E of sheet-iron or steel is suspended concentrically with the electrodes. This ring which is partially immersed in the electrolyte produces at the surface of the bath an effective separation between the oxygen rising from the anode (which escapes externally) and the hydrogen together with the sodium rising from the cathode (which collects in the interior). The vat. A rests upon a stoneware base F,the latter having an interior vto prevent-radiation as far as possible so as to permit of the bath of caustic soda being maintained at a fusion temperature.

In order to setthe apparatus in action the vessel A is filled with caustic soda in frag ments and the electric current is caused to.

traverse the conductor G; the intensity of the current is regulated so as to bring the conductor tored-heat. Theheat disengaged is absorbed by the metal of the vat and the soda which it contains becomes fused. As

soon as the vessel is full of liquefied soda the current is stopped flowing in the heating circuit G and the apparatus is ready for work. I

The production of sodium is initiated by passing a continuous current, whose intensity is proportioned to the dimensions of the apparatus and under a pressure of about 5 or 6 volts, the resistance which the current experiences in traversing the bath causing.

the development of sufiicient heat to maintain the soda in the fused state. Under the electrolytic action of the current, free oxygen is formed-at the anode and is disengaged at the surface externally of the separator E (Fig. 2), while the hydrogen and sodium simultaneously escape from the cathode in globules and both appear at the surface of the bath in the interior, of the ring E] The sodium collects in drops resembling melted white wax, and it is removed by means of a perforated ladle which only permits the passage of the fused soda.

The apparatus is charged periodically with soda to replace that which has been decomposed. The mean level of thebath is indicated at J. The essential features of this apparatus may be stated as follows.

The cathode formed of spaced rods, con- StltutOS'b. great spherical development of the two electrodes, but whereas the anode has a large surface actually exposed to electrolytic action. the cathode, whose activity is con- ,centrated upon its rods. presents on the connot only serves to guide the ascent of the sodium, but also enables the use of a diaphragm to be. dispensed with. After the apparatus has been in action for a time which may vary between wide limits 24 01'48 hours) a gradual and progresslve diminution in the production of the sodium may be observed. The output gradually diminishes up to a 50% reduction and it may also happen that the bath becomes excessively'heated, while the formation of $0 dium becomes insignificant and this without any apparent externalcause.

According to the invention forming the subject of the present application, it is by renewingthe active surface of the cathode that the normal efliciency of an apparatus of this kind is restored. In order to efiect this result the electrolyzing current is momentarily stopped and the fixed cathode is detached from its support and is then withdrawn from the bath, whereupon the rods are plunged into water or into an aqueous solutionsuch as soda-lye. After the'conelusion of this washing operation, wlnch may be rapidly carried out Without any danger (by immersion or by aspersion) the v cathode is replaced and fixed in position, the current is restored and the sodium is soon seen to make its appearance in the form of sufiiciently large globules. Thus by a periodical washing of the cathode a normal and practically continuous working of an apparatus of this kind may be obtained. This periodical washing operation is an essential feature of the process and constitutes one of the characteristics of the inven-v tion.

Figs. 4 and 7 represent at E a modifiea-- tion of the separator formed of a tabulated plate having a rabbeted margin, beneath .which the sodium collects and whence it finally passes into the tubulure e from which it may be extracted. By the use of this closed separator the sodium is protected against the action of the surrounding air and the alkaline projections are very attenuated. This collector provided with a lid is preferable to the open ring which it replaces. The apparatus thus constituted admits of various other modifications in its details, for example, it may be constructed with'plane parallel electrodes without altering its fundamental characteristics. A transformation of this kind is quite naturally derived from the circular form whereof it is simply a rectilinear truncated development. Figs. -8 and 9 show respectively a plan and a vertical section of an apparatus constructed with multiple, alternateplane electrodes B and t, the whole assemblage having an anode at each side. WVith this 1 modification all the essential constituent elements of the fundamental type are retained as are also their properties and mode of operation. The vessel wherein the sodium collects, becomes in this rrangement an elongated frame such as E Furthermore with this modification a closed -"separator on the principle of that represented at E may be adopted. I Each cathode'is provided with a separate collector. The anodes B consist of sheet metal stripsand the cathodes-D have the general shape. of a comb or rake. The

invention is otherwise independent of the' forms, dimensions and detail-arrangements of the various elements which constitute the complete apparatus above described.

3. In an apparatus for the electrolytic manufacture of sodium a cathode consisting of vertically disposed separated rods hanging below a common carrier, anda flat colmanufacture of sodium a cathode consisting of separated vertical rods hanging below a common carrier, a suspension rod at the center of this common carrier, a flat sodium collector provided with downwardly. flared edges provided atvits center with an aperture provided with a sleeve for the passage of the cathode carrier and provided on its side with a sodium pot.

5.. In an ap aratus for the electrolytic manufacture of sodium a cathode consisting of separated vertical rods hanging below a common circular carrier, a suspension rod at the center of this common carrier, a flat circular sodium collector provided with downwardly flared edges, provided at its center with an aperture provided with a sleeve for the-passage of the cathode carriergand provided on its side with a sodium ot. p 6. In an apparatus for the electrolytic manufacture of sodium, a cathode consisting of separated vertical rods hanging below a common carrier, a sodium collecting dish a vat and a zig-zag shaped electrical heating device disposed under the vat.

7. In an apparatus for the electrolytic manufacture of sodium, a,cathode consisting of separated vertical rods suspended from a common carrier, a sodium collecting dish, a vat, and an electric heater under the vat.

The foregoing specification of my means for the electrolytic manufacture of sodium signed by me this 16th day of October, 1908.

PAUL LEON HULIN. Witnesses:

DEAN M. MASON, MAURICE I-I. PIGNET. 

